1. Field of the Invention
The present invention relates to a headlamp light distribution control device that performs switching control of an irradiation direction of a vehicular headlamp.
2. Description of the Related Art
In the related art, there has been known a device that automatically switches an irradiation direction of a vehicular headlamp (headlight) to be moved up and down based on whether or not a vehicle is present in front of own vehicle. This device detects a lamp such as a tail lamp (tail light) mounted in a forward vehicle from an image of an area in front of own vehicle obtained by a camera. If a lamp is detected, the device judges that the forward vehicle etc. is present, and then switches an irradiation direction of a headlamp of own vehicle (see, e.g., JP-A-2008-037240).
In addition, there has been known a method called “ADB (adaptive driving beam)” that is used for controlling an irradiation direction of a vehicular headlamp so as to be displaced laterally outwardly, if a forward vehicle is present, in order to prevent a driver of the forward vehicle from being dazzled by irradiating the headlamp of own vehicle to the forward vehicle.
In the related art, the lamp of the forward vehicle is detected based on only the image obtained by the camera. In this case, for example, if a distance to the forward vehicle is large, a tail lamp actually composed of a pair of lamps cannot be judged as being two lamps, but may be judged as being one lamp, due to the finite resolution of the camera.
The above judgment that the tail lamp is one lamp may be caused by malfunction of either of two lamps, or by the finite resolution of the camera despite normal lighting of both of two lamps. This makes it difficult to determine why the pair of lamps mounted in the forward vehicle is judged as being composed of one lamp.
ADB control is performed so as to irradiate the outside of the lamp. Due to this, if one of two lamps is malfunctioning and then cannot be lit, the outside of the other of two lamps which is lit is irradiated. This results in irradiation of a seat position of the driver of the forward vehicle, thereby dazzling the driver of the forward vehicle.